Remove config option options.openLinksWithDefaultApp

[kulmann]

Describe the bug

We introduced the config option options.openLinksWithDefaultApp because we were afraid poeple would be confused that they are routed into the editor instead of seeing a single file public link in the files app first. Reality check: doesn't do any harm. So let's remove the config option and always route into the editor (which was the default behaviour of the config option).

Please remember to also remove the config option from the ocis config struct.